title: Trial of different intensities of anticoagulation in patients with prosthetic heart valves.
abstract: We compared the efficacy and complications of anticoagulation with warfarin in 258 patients with prosthetic heart valves treated with regimens of "moderate intensity" (prothrombin-time ratio, 1.5; international normalized ratio, 2.65) or "high intensity" (prothrombin-time ratio, 2.5; international normalized ratio, 9) in a prospective, randomized study. The two patient groups were followed up for 421 patient-years and 436 patient-years, respectively. Eleven patients were lost to follow-up. Thromboembolism occurred with similar frequency in the two groups (4.0 and 3.7 episodes per 100 patient-years, respectively), but there was a total of 6.2 bleeding episodes per 100 patient-years in the moderate-intensity group, as compared with 12.1 episodes in the high-intensity group (P less than 0.002). There were 5.2 episodes of minor bleeding per 100 patient-years in the moderate-intensity group, as compared with 10.1 episodes in the high-intensity group (P less than 0.01). Major bleeding was also more common in the high-intensity group (2.1 episodes per 100 patient-years--including the only two fatal hemorrhages--as compared with 0.95 episode in the moderate-intensity group), but the difference was not statistically significant. We conclude that a moderate anticoagulant effect (prothrombin-time ratio, about 1.5) in patients with a mechanical prosthetic heart valve offers protection equivalent to that of more intensive therapy, but at a significantly lower risk.
authors.affiliation: Department of Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
authors.forename: J N
authors.initials: JN
authors.lastname: Saour
authors.forename: J O
authors.initials: JO
authors.lastname: Sieck
authors.forename: L A
authors.initials: LA
authors.lastname: Mamo
authors.forename: A S
authors.initials: AS
authors.lastname: Gallus
mesh_terms: D000293:Adolescent; D000328:Adult; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D002648:Child; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011517:Prothrombin Time; D011897:Random Allocation; D013923:Thromboembolism / Q000097:blood / Q000209:etiology; D014859:Warfarin / Q000008:administration & dosage
chemical_list: D000925:Anticoagulants; D014859:Warfarin